1. K. Brünnler, Deep Inference and Symmetry in Classical Proofs, Ph.D. thesis, Technische Universität Dresden, September 2003.
2. The undecidability of k-probability;Buss;Annals of Pure and Applied Logic,1991
3. A. Carbone, Some combinatorics behind proofs, in preparation. Available from: %3cwww.univ-paris12.fr/lacl/ale/comb.ps.gz/%3e.
4. Interpolants, cut elimination and flow graphs for the propositional calculus;Carbone;Annals of Pure and Applied Logic,1997
5. A Graphic Apology for Symmetry and Implicitness. Mathematical Monographs;Carbone,2000